Gudgeon-pin bush for pistons



R. ALLEN.

GUDGEON PIN BUSH FOR PISTONS.

APPLICATION man MAR. 2. 1920.

1,415,422, mummy 9,1922.

2 SHEETS-SHEET l- 1715 .6. Figa E RLALLEN. GU DGEON PIN BUSH FOR PISTONS. APPLICATION FILED MAR. 2, 1920.

1 ,41 5 Patented May 9,1922.

2 SHEETS-SHEET 2.

. member is e'UneEoN-rm Bose FOR PISTONS.

' Specification of Letters Patent.

' Application filed March 2, 1920. Serial No. 362,706.

To all whom it may concern: a i

Be it known that I, ROBE T ALLEN, a subject ofthe King of Great Britain and Ireland, and a resident of Ghiltern Rise, Woodcote, Reading, county of Berkshire, England, have invented certain new and useful Improvements in Gudgeon-Pin Bushes for Pistons, of which the following is a specification.

The present invention has for its objects an improved gudgeon pin bush for pistons and also an improved method of fitting the bush to the piston and is particularly applicable to pistons made of alumin1um or similar alloys. I i

According to the present invention a compound bush comprising inner and outer members is employed, the outer member of which is either cast into the iston or pressed into ahole in the heated piston so that on cooling the contraction of the pistonxholds the'meniber firmly in' place, and the inner member of the bush which is of malleable or cast steel case hardened on its insideis accurately machined to fit tightly Within the outer member and receive 'tliegudgeon pin. In the event ofthe outer member being cast into the piston, thepartsof the piston surrounding the bushes are preferably formed with recesses adapted to mould keying projections on the outer member of the bush in order to prevent rotary or end'movement of the member within the piston. The outer member of the bush is able unhardened steel alloy and the inner preferably a malleable cast machined liner. Discs or end shields of brass, copper or other non-scoring metal may be inserted in the bushes at the gudgeon pin ends to prevent the pin marking the cylinder walls.

Two examples of the present invention are illustrated in the accompanying drawings wherein Figure 1 is a vertical section of a piston and gudgeon pin with the improved bush and protector pads or shields of brass or copper applied.

Figure 2 is a vertical section of a piston wherein a modified form bush is applied.

Figures 3 and 4 are end elevation and vertical section of the outer member of the bush and Figure 5 shows in vertical section the inner member of the bush.

Figures 6 and 7 are face and edge elevathe other endof copper protector pads cl maybe pressed into preferably of a suittions of the protector pad or shield shown in igure'l and Figures 8 and 9 are similar views showing a modified form of protector pad or shield. Inthe form of v the invention shown in Figure '1 the improved bush comprises the outer member a of unhardened nickel steel which in this case-is cast in. an aperture in the'piston and a malleable or 'cast-inner flanged member a both of which are accurately machined so that'theinner member within the'outer member a. The walls of the apertures in the piston are slotted intermittently in" order to produce 6 fits closely a series of projections c onthe' bush member to'key the piston. 1 1 The inner member 6 of flthe bush which is placed in position from-withinthe piston within the bush and An annular groove the outer end of the outer bush'memb'eraat the pin in order that-the place, and engage the grooves when the pin is in position to serve as shields to prevent the pin scoring the cylinder" walls. As shown in Fignresloand 7 the protector discs Z are formed with radial springinto placeand their edges then engage the annular grooves in the bushes.

In the form shown in Figure 2 the outer member a of the compound bush is cast inv The grooves place in the piston as before. cut in the inner walls of the piston apertures areshallow and produce a series of keying projections 0 around the outer bush member asseen in Figures 3 and 4:. In the example the protecting disc of copper or the like 1 ratenteaiuaye; 1922.

same in place and thereby pre-' vent rotary or end movement within the 9o slots (Z around. their edges in order that-they may readily I of bushing is particularly applicable to pistons made of alu-.

minium and similar alloys but it can of course be applied to cast iron and steel pistons. In the event of wear setting in at the bush all that is necessary is to replace the inner member of the bush and thereby a great saving is effected.

In some cases instead of casting the outer member of the bush as described it may be machined slightly larger than the hole in the piston and pressed into position after the piston has been heated to enlarge the hole, being firmly held by the subsequent contraction of the piston in cooling.

I claim 1 The improved pistons comprising and an inner bush closely within the outer receive the gudgeon pin.

2. The improved gudgeon pin bush tor pistons comprising an outer bush member. an inner bush member fitted closely within the outer member to receive the gudgeon in and a shield of likenon-scoring metal fitted in the bush to cover the end of the gudgeon pin substantially as described.

3. In the improved gudgeon pin bush ior pistons as claimed in claim 2, in which said shield is in the form of a disc slotted radially at its edges in order that it may be pressed. into and retained in an annular internal roove in one of the bush members.

l. In the improved gudgeon pin bush for pistons as claimed in claim 2, in which said shield is in the form of a plate of metal gudgeon pin bush for an outer bush member member adapted to fit bush member and having edge portions shaped to fit into an internal annular groove formed in one of: the bush members.

5. The comblnation with a piston and lts pin of a relatively-fixed shield extending over the end of the pin to prevent the latter from scoring the cylinder wall.

6. The combination with a piston and its pin, of an outer bush member fixed in the piston. a removable inner bush member fitted in the outer member to receive the pin, and a shield engaging one of the bush members and limiting ,endwise movement of the pin in one direction.

7. The combination with a piston and its the former having spaced pin-bearings, of an outer bush member fixed in each bearing a removable inner bush. member fitted in each outer member for receiving the pin, each inner bush member having its inner end flanged to limit its outward movement. the outer end of one of the inner bush members and the outer end of one o'f'the outer bush members being grooved, and shields fitted in said grooves to limit the longitudinal movement ot'the pin in the inner bush members. v

8. The combination with a piston and its pin, the former having spaced pin-bearings, of an outer bush member fixed in each bearing. a removable inner bush member fitted in each outer member to receive the pin, and means for limiting the outward longitudinal movement of the inner members in the outer members. a v

9.'The combination of a piston of relatively-soft metal having pin bearing openings. outer bush members of a relativelyhard metal rigidly and permanently secured in said openings, and pin-receiving inner bush members removably fitted in the outer members.

In testimony whereof he afiixed his signature.

ROBERT ALLEN. 

